1. Transportation Center, Northwestern University, 215 Chambers Hall, 600 Foster Street, Evanston, IL 60208.
2. Department of Environment, Land, and Infrastructure Engineering, Politecnico di Torino, Corso Duca Degli Abruzzi, 24-10129 Torino, Italy.
3. Civil and Environmental Engineering Department, School of Engineering and Applied Science, George Washington University, Room 201-I, 20101 Academic Way, Ashburn, VA 20147.